Astronomy:Pi1 Pegasi
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 09m 13.61893s[1] |
| Declination | +33° 10′ 20.4778″[1] |
| Apparent magnitude (V) | +5.58[2] |
| Characteristics | |
| Spectral type | G8IIIb[3] |
| B−V color index | +0.985±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | +5.1±0.9[4] km/s |
| Proper motion (μ) | RA: −48.117[1] mas/yr Dec.: −73.408[1] mas/yr |
| Parallax (π) | 10.2111 ± 0.1137[1] mas |
| Distance | 319 ± 4 ly (98 ± 1 pc) |
| Absolute magnitude (MV) | 0.84[5] |
| Details | |
| Mass | 2.48[6] M☉ |
| Radius | 11.00+0.51 −0.83[1] R☉ |
| Luminosity | 62.8±0.8[1] L☉ |
| Surface gravity (log g) | 2.7[7] cgs |
| Temperature | 4,898+196 −110[1] K |
| Metallicity [Fe/H] | −0.22[5] dex |
| Rotational velocity (v sin i) | 135[7] km/s |
| Age | 530[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi1 Pegasi, Latinized from π1 Pegasi, is a star in the constellation Pegasus. Based upon changes to the proper motion of the visible component, this is a probable astrometric binary.[9] It has a yellow hue and is dimply visible to the naked eye with a combined apparent visual magnitude of +5.58.[2] The system is located approximately 319 light years distant from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +5 km/s.[4] It is a member of the Ursa Major Moving Group of co-moving stars.[10]
The visible component is an aging giant star with a stellar classification of G8IIIb.[3] It has a high rate of spin, with a projected rotational velocity of 135 km/s.[7] This is giving it an equatorial bulge that is 17% larger than the polar radius.[11] It is a shell star, being orbited by a circumstellar shell of cooler gas.[12][13] This star is 530[6] million years old with 2.5[6] times the mass of the Sun. With the supply of hydrogen exhausted at its core, the star has cooled and expanded to 11[1] times the Sun's radius. It is radiating 63[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,898 K.[1]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Abt, H. A. (September 1985), "Visual multiples. VIII. 1000 MK types", Astrophysical Journal Supplement Series 59: 95–112, doi:10.1086/191064, Bibcode: 1985ApJS...59...95A
- ↑ 4.0 4.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 5.0 5.1 Takeda, Yoichi et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan 60 (4): 781–802, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T.
- ↑ 6.0 6.1 6.2 6.3 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ 7.0 7.1 7.2 Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M
- ↑ "pi Peg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi+Peg.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Schmitt, J. H. M. M. et al. (March 1990), "X-ray studies of coeval star samples. III. X-ray emission in the UrsaMajor stream.", Astrophysical Journal 351: 492–499, doi:10.1086/168486, Bibcode: 1990ApJ...351..492S.
- ↑ van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
- ↑ Hauck, B.; Jaschek, C. (February 2000), "A-shell stars in the Geneva system", Astronomy and Astrophysics 354: 157–162, Bibcode: 2000A&A...354..157H.
- ↑ Slettebak, A. (September 1986), "H-alpha and near-infrared spectra of late-type Be and A-F-type shell stars.", Publications of the Astronomical Society of the Pacific 98: 867–871, doi:10.1086/131836, Bibcode: 1986PASP...98..867S.
External links
- Kaler, James B., "Pi Pegasi", STARS, http://stars.astro.illinois.edu/sow/pipeg.html.
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